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Neuronal studies on fruit flies can tell us more about brain plasticity.

Profiling Optic Lobe Neurons in the Fruit Fly

September 03, 2014

What makes one cell develop differently from another? Postdoctoral Associate Katarina Kapuralin is working to answer that question at NYU Abu Dhabi's Center for Genomics and Systems Biology. With Professor Claude Desplan's lab, Kapuralin is trying to learn how optic lobe neurons develop their specificity in the fruit fly brain.

The study of genomics has developed rapidly over the past decade. The genomes of several species — including humans — have been sequenced. This work has taught researchers about the similarities and differences among species and how they diverge. But there are many more questions to answer.

"We don't know much about particular cells and how they develop differently from each other," Kapuralin explained. "So we want to learn more about the expression of the genes and transcription factors in a specific cell."

Kapuralin's research progresses in several stages. She works with fruit flies (Drosophila melanogaster) that have been altered genetically. The first step is to make sure that the fly lines she works with have the modifications in one neuronal subtype only. This can be done by inserting green fluorescent protein (GFP) into specific genes. The GFP is expressed in the flies' optic lobe neurons and allows researchers to identify this subset of neurons visually, under a microscope.

She then takes a random selection of flies from a particular strain and analyzes their neurons under a confocal microscope, to make sure that only one subtype of optic lobe neurons in the fly brain expresses the GFP.

Once she has identified a suitable line, she dissects many fly brains and further analyzes them on a FACS (fluorescence-activated cell sorting) machine that separates the optic lobe neurons that express GFP from other cells in the fly brain.

The sorting allows her to get a very specific sample of optic lobe neurons; she then conducts RNA deep sequencing on these cells. "This detailed analysis will allow us to see the complete gene-expression profile of individual optic lobe neurons, and we will be able to correlate this transcriptome with their different defining characteristics," Kapuralin said.

Once completed, this cutting-edge work may help the researchers understand how cell differentiation is carried out in the brain of fruit flies. And that knowledge could have wider implications for showing researchers how cells in organisms achieve their specificity.